The Advanced Backeross Population Population In Maize In The Response To Low Nitrogen Stress And Low Phosphorus Stress

It is an effective means to decrease the negative influence of unreasonable fertilizer management by the means of genetic improvement for the different nutrient efficient plants. Furthermore, it can decrease the costs of production and increase the efficiency of fertilizer, especially nitrogen and phosphorus. So we can hope to enhance the efficiency of breeding by combine the research of physical and genetic mechanism under nutrient (N, P) stress with MAS (marker assisted selection) in maize. In this dissertation, we designed three treats as follows: N stress, P stress and N, P normal. The materials were the advanced backcross population (BC4F3), the donor parent was 478 and the recurrent parent was Wu312. We measured agronomic traits, grain yield and related traits. The objective was to evaluate the advanced backcross population under N and P stress. At the same time, these data would be the good foundation for the next QTL analysis.Our result indicated:1. In 2007, for the whole population, the grain yield decreased 2.9% and leaf area and ear height increased 10.3% and 7.8%, respectively, under P stress. And under the N stress, the grain yield decreased 12.8% significantly, row numbers decreased 10.1%, leaf area and SPAD decreased 7.9% and 13.7%, respectively.2. In 2008, the grain yield decreased 35.3% significantly, rows number decreased 19.5% and other ear related traits decreased 5%, and agronomic traits (leaf area, plant height, ear height and SPAD) decreased 4% to 10% under P stress. For the N stress, the grain yield decreased 8.5%, ear related traits decreased a little, SPAD decreased 12.2%, but all the traits were not significantly with the normal nutrient treatment.3. There were significant correlations between the grain yield and ear length, ear diameter, ear rows number, row grains, leaf area, plant height, ear height and SPAD under the different treatment. Of these traits, the correlation coefficients of rows number, ear diameter, plant height and leaf area were higher.4. Of the advanced backcross population, L128 had the better grain yield and related traits under the field conditions; L170 had the better root system under the paper and water culture and L177 had the better root related traits under the sand culture.5. Of these culture systems, the sand culture was profit to research the simulation of nitrogen for the seminal root system and the hydroponics was more profit to study the effect of nitrogen for the crown roots.